Quantum Cellular Automata (QCA) has been proposed as an alternative
architecture to CMOS and in principle should permit the implementation of ultra
lower-power, nano-scale logic circuitry working at teraflop frequency. QCA is
based on a new paradigm for encoding binary logic into electronic circuitry,
where binary 1s and 0s are mapped to spatial configurations of electrons rather
than magnitudes of electronic currents. The layout rules for QCA based
circuits are radically different from those of CMOS based circuits, and design
automation tools for QCA circuit layout are hard to find. This paper discusses
the first automatic global placement algorithm for QCA-based circuits. We
divide the QCA global placement process into zone partitioning and zone
placement, and identify the constraints and objectives that are unique to
QCA-basec circuits as opposed to the conventional CMOS VLSI.